Course Title: Using Epi Info™ 7 Using Classic Analysis (Continuation) April Epi Info™ 7 Training Software for Public Health Epi Info™ 7 Training Software for Public Health Epidemiology and Analysis Program Office Office of Surveillance, Epidemiology, and Laboratory Services

Module 6 – Part II Outline  Basic Analysis Statistics PowerPoint Slide Presentation  Instructor demonstration Analysis, Creating Statistics  Students practice  End of Lesson Questions

Classic Analysis – Creating Statistics  Interested in discovering from the data?  The frequency of Ill cases  What is the average age for cases who got ill?  Is there a strong relationship between ill cases and a specific food item that was consumed?

Classic Analysis Commands  DISPLAY  SET  FREQUENCIES  MEANS  TABLES

Creating Statistics  Use the FREQUENCY command to discover the distribution of the population based on geneal demographic information.  Use the TABLES command to discover the odds and risk ratios for foods eaten.  Use the MEANS command to find out average age of cases.

DISPLAY command  The DISPLAY command allows the display of metadata information about tables, forms, and database information.

DISPLAY output

SET command  The SET command provides various options that affect the performance and output of data in Classic Analysis.  These settings are utilized whenever the Classic Analysis program is used.  Some of these settings will be available in a future Epi Info 7 release.

SET command

FREQuency command  Produces a table showing how many records have each value for the specified variable(s).  A Weight variable is selected for use in weighted analyses or when the current dataset consists of summary data.  Stratify By identifies the variable to be used to stratify or group the frequency data.  Output to Table field identifies a data table to receive output from the command.

FREQ command FREQ Died

MEANS command  Used when variable of interest is numeric and measured on a continuous scale.  Means Of identifies the variable whose mean is to be computed.  A Weight variable is selected for use in weighted analyses. The weight variable applies to all aggregation clauses.  The Output to Table field identifies a data table to receive output from the command.  The Cross-Tabulate by Value of variable is used to cross-classify data.  Stratify By identifies the variable to be used to stratify or group the means data.

MEANS command MEANS Age Sex

TABLES command  Performs a cross-tabulation of the specified variables In other words, it examines the relationship between two or more categorical values.  In this test scenario, you might want to know if there is an association of consuming Strawberries or Cooked Bacon with getting ill.

TABLES command  A Weight variable is selected for use in weighted analyses or when the current dataset consists of summary data.  Stratify By identifies the variable to be used to stratify or group the data.  Output to Table field identifies a data table to receive output from the command.

TABLES command TABLES Strawberries Ill

Glossary of Terms  Odds Ratio – measure of effect size, describing the strength or non-independence between two data values.  Risk Ratio – measure of a risk and if being exposed to a factor increases the probability that an event will occur  P-Value - probability of observing the value of the significance test (< 0.05 is often considered “significant”)  Confidence Interval - A range of values for a variable that indicates the likely location of the true value of a measure.

Saving an Epi Info™ Program  In order to re-create the same statistics after data has been added, you want to save the program or code.  You can run these same statistics on the new records as many times as possible.  From the Program Editor, click File>Save Pgm. The Save Program dialog box opens.  Click TEXT FILE option  Name Program as desired (i.e. Program1)  Save file in desired location.  Click Save  Click OK

Saving an Epi Info™ Program

Running a Saved Epi Info™ Program  From the Program Editor, select File > Open Pgm or click the Open Pgm icon. The Read Program dialog box opens.  Click Text File to view all available.pgm files.  Click OK. The program code opens in the Program Editor.  Click Run Commands. The Program Editor runs all the code listed and displays the results in the Output window.  To run individual commands, use the cursor to highlight the commands you want to run. Click Run Commands.

What Have You Learned!  Use the DISPLAY command to view variable types in your project.  Use the FREQ command to see how your data is distributed.  Use the TABLES command to see if risk factors are linked to outcomes.

What Have You Learned!  Use the MEANS command to see if one set of data is equal to the sum of the data divided by the number of items in the data set.  Save Program (.PGM) files for use with later data tables or updated data.

For more information please contact Centers for Disease Control and Prevention 1600 Clifton Road NE, Atlanta, GA Telephone, CDC-INFO ( )/TTY: Web: Questions? Office of Surveillance, Epidemiology, and Laboratory Services Epidemiology and Analysis Program Office The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.